I suspect there isn't a management tool out there that does the
right thing today.

I suspected as much based on how strongly you were advocating this.

You're a little too suspicious. RHEV-H has nothing to do with my
opposition to -net bridge.

I think my point still stands though, there's an awful lot of
management software out there that gets it wrong. It's great that
you guys got it right but so far, the majority of users are not using
qemu through RHEV-M so I still think we have a problem.

I'm worrying that we're transforming one problem into two different
ones. Expanding the scope of qemu, and making it more difficult to
use advanced networking functionality.

Do you object to the idea of having qemu call to a helper program
directly or to the idea of having the helper program in qemu at all?
Splitting the helper into a separate project may be a more constructive
discussion as was suggested by Arnd.

As a separate project, libvirt could also make use of it and use -net
tap,fd= if it wanted to do crazy things. From a distro perspective,
it's just a matter of setting up dependencies to make it Just Work so I
don't object to it that much. It's just a bit annoying to create an
entire new project for a few hundred line helper.